The present invention relates to a seal structure for an electronic control device, which is favorable for an engine control unit or an automatic transmission control unit.
As an example of the seal structure for the electronic control device, it is disclosed in Japanese Patent Provisional Publication No. 2009-070855 (hereinafter is referred to as “JP2009-070855”). In JP2009-070855, the seal structure of a connector part of a so-called connector-side-mounted type of electronic control device, in which a part of the connector fixed to one side of a circuit board is exposed to an outside of a casing from a window of the casing, is disclosed. Both upper and lower surfaces of the connector are sandwiched between and by a pair of members of the casing from width direction of the circuit board. Then, a connector seal portion, which is filled with a sealing material, is provided at a fitting surface portion between an outer peripheral surface of the connector and an inner peripheral surface of the casing throughout the entire circumference of the connector. This connector seal portion is formed by a seal groove and a protruding line which are provided respectively at one side and the other side of the connector and the casing so as to secure a predetermined seal length (also called a leak path). A U-shaped gap formed between these seal groove and protruding line is filled with the sealing material.